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PENGOLAHAN DATA SEISMIK

By : Ardian Novianto

5/28/2018 Datum Corection

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1. Koreksi efek near-surface (weathering layer/inconsisten layer)

2. Penggantian inconsistance layer

3. Memodelkan kembali lapisan near surface

Tahapan yang harus dilakukan dalam koreksi Datum :

-

Datum

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PENGOLAHAN DATA SEISMIK

By : Ardian Novianto

model

Sub-modelLayer

Base Horizon

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STRIPPING:

TG= - U + TSELVS - D - ELVB

VNS

TS = - and

Where V = kece atan rata-rata dari bottom luban ke base horizon

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PENGOLAHAN DATA SEISMIK

By : Ardian Novianto

U = pengukuran uphole timeD = kedalaman shot

ELVDAT - ELVB

VR

TR =+ * 2REPLACEMENT:

T = TS+ TG+ TRTOTAL sifting :

Where VR = Kecepatan pengganti(replacement velocity)

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Quis

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PENGOLAHAN DATA SEISMIK

By : Ardian Novianto

-

-

?

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A 135B 110

C 95D 65

E 20

0.024

0.030

0.036

0.022

0.014LVL

Surface Elevation

72

70 80

6560 shot Depth

LVL

DATUM

SEA LEVEL

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PENGOLAHAN DATA SEISMIK

By : Ardian Novianto

LOCATION UHT SHOT TO

DATUM TIME

SURFACE TO

DATUM TIME

A 0.024 0.008 Sec 0.032 Sec

B 0.030 0.005 Sec 0.035 Sec

C 0.036

D 0.022

E 0.014

Shot Location Geophone

location

Static Corrections

B A - (0.005 + 0.032) = - 0.037

C A - (0.002 + 0.032) = ?

D B

E C

E D

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1. Perhitungan Shot to datum Time :

Shot to Datum Time = Elevation Shot depthDatum Velocity

Diketahui besarnya Datum Velocity = 8000/sec.- Titik A : Shot To Datum time = 135 72

8000

= 0.0079 Sec- Titik B : Shot To Datum time = 110 70

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PENGOLAHAN DATA SEISMIK

By : Ardian Novianto

8000= 0.005 Sec

2. Perhitungan Surface to datum Time :

Surface to datum Time = UHT + Shot to Datum Time

- Titik A : 0.024 + 0.008 = 0.032 Sec- Titik B : 0.030 + 0.005 = 0.035 Sec

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3. Perhitungan Static Corecctions

Static Correction = - (Shot to Datum Time + Surface to Datum Time)

Tanda Minus disini merupakan koreksi terhadap posisi datumnya denganasumsi bahwa terdapat kelebihan waktu diatas posisi datum sehingga harusdikurangkan.

-Shot Location B dan Geo hone Location A

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PENGOLAHAN DATA SEISMIK

By : Ardian Novianto

= - (Shot to Datum Time B + Surface to Datum Time A)= - (0.005 + 0.032)= - 0.037 Sec

-Shot Location C dan Geophone Location A= - (Shot to Datum Time C + Surface to Datum Time A)

= ??